Grade averaging computer



Oct. 3, 1961 i P. MXROWLAND 3,002,683

.GRADE AVERAGINQ COMPUTER Filed Nov. 15. 195'? v 2 sheets-sheet 1 F/G 2f5 u 6 H6 6 A ,3 F/G 7 A 7 ran/vtr.:

Oct. 3, 1961 P. M.RowLAND I 3,002,683

GRADE AVERAGING COMPUTER Filed NOV. 15. 1957 2 Sheets-Sheet 2 J/vvE/vroePAUL 'M @0n/LAND United States Patent 3,002,683 GRADE AVERAGING CGMPUTERPaul M. Rowland, 416 W. North St., Warrensburg, Mo. Filed Nov. 15, 1957,Ser. No. 696,834 1 Claim. (Cl. 23S-83) This invention relates tocomputing devices, and more particularly to a device for obtaining theaverage of a number of grades. t

A main object of the invention is to provide a novel and improved gradeaverage computer which is simple in construction, which is easy tooperate, and which provides a means of rapidly and accuratelydetermining the average of a number of alphabetical grades.

A further object of proved grade average computer which is inexpensiveto manufacture, which is compact in size, which is durable inconstruction, and which is especially useful for teachers andinstructors for finding the final average grade for a student fromseveral alphabeticalv letter grades, or for otherwork, such as inconnection with tests and measurements. f

Further objects and advantages of the invention will become apparentfrom the following description and claim, and from the accompanyingdrawings, wherein:

. FIGURE l is a top plan view of an improved average` grade computerconstructed in accordance with the present invention. l

` FIGURE 2 is a vertical cross sectional view taken on the line 2-2 ofFIGURE 1. t

FIGURE 3 is a top plan view of the ratchet disc mem-` ber `employed inthe average grade computer of FIG- URESlandZ. f

FIGURE 4 is a top plan view of the device of FIGURE 1 with the top coverand ratchet disc removed.

FIGURE 5 is an enlarged perspective view of-themanually t perated stoplever employed in the grade average computer of FIGURESlto 4. f f jFIGURE 6 is an venlarged cross sectional detail view taken on the line6--6Vof FIGURE 4.

pFIGUREr7 isan enlarged cross' sectional detail view taken on the line7--7 of FIGURE. y

Referring to.the. drawings, the grade `average, computingdevice ,isdesignatedgenerally at 11 vand comprises a generally circularLbase.12,having an upstanding` periph-` eralwall 13which detines algenerally.. circular recess in the base. .Thebaseis rformed vwith alaterally extending thickened portion 14 which merges with theupstanding peripheral -wall 13, as is clearly shown in FIGURE :4, said"thickened yportion 14 ,defining ,ai projectionat one side of the basewhichmaybe employed as a holding means for thefcomputer. Opposite theenlarged side portion14,A the base 12 is formed with a generallyV-shaped recess 15 lwhich includesthecenterof the base, as shown inFIGURE 4. Designated at 16'is an arm which is disposed in the recess 15,the arm being substantially dat, as shown,and being pivotally engaged-onan upstanding central` stud -17 provided on the base, .the recess 15being arcuately formed atits inner-end,.as shown at.18, and the arm16being similarlyarcuately formed at 19 so that the armiis freely.rotatable `through the angle dened by the generally V-shapedrecess 15. l

Arm-16 is formed with the outwardly projecting, reduced operating `lug20, said lug being providedrwith a radially'extending index mark 21`located outwardly adjacent theperiphery of baseY 12. Mounted on the arm16 adjacent the periphery of the base 12 Yis a resilient pawl spring"22, said spring projecting inwardly and upwardly, as viewed in FIGURE4,` whereby it is yieldabler when the arm4 ismoved in a downwarddirection but is relatively rigid when the arm is moved upwardly, aswill bepresent-VVV 1y described.

the invention is to provide an imice i Y 2 Designated at 23 is aresilient pawl member which is embedded in the thickened portion 14 andwhich projects into the generally circular recess defined on the base 12by the peripheral wall thereof, the leaf spring member 2?V extendingdownwardly and inwardly into said recess, as is,

clearly shown in FIGURE 4, whereby it is yieldable in one direction andsubstantially rigid in another, as will be further described.

' Designated at 24 is a ratchet disc which is rotatably received in thecircular recess defined in the base 12, ratchet disc 24 being formedwith a central stud portion 25 which is centrally recessed at its bottomsurface to rev 28.` Said rim member 27 lis further formed with theevenly kspaced ratchet teeth 28 which are engageable by thepawl members22 and 23, whereby the pawl member 23 is yieldable when the kdisc member24 rotates in a counterclockwise direction, as viewed in FIGURES 3A `and4, the pawl`rnember 23 acting to prevent clockwise rotation of the discmember 24. The pawl member 22 on the arm 16 is arranged to drivinglyengage the ratchet teeth 28, whereby the disc member 24 may be rotatedin -a counterclockwise direction by rotating the arm 16 in saiddirection, using the handle element 20. The ,arm 16 may be returned in aclockwise direction, as viewed in FIG- URE 4, without rotating the discmember 24, since the pawl spring 22 is yieldable to allow arm 16 torotate clockwise relative to the ratchet disc 24.

Designated at 29 is a manually operated locking lever, comprising a atbody 30 formed at one end with an arcuate detent shoulder 31 having acurved cam-like leading edge 45 and at its other end with an upstandingstud 32. Thelever 29 is pivoted at its intermediate portion to the base12 adjacent theperipheral wall 13, the peripheral wall being arcuatelynotched at 33kto allow clearance for the outer end of lever 29, as showniny FIGURE 4. The body 30 of the locking lever 29 lies in a generallycircular recess 43 in base 12 and extends beneath the rim 27'of thedisc' 24, and the detent shoulder 31 extends upwardlyand inwardlyadjacent the internal shoulder 28'. Said internal shoulder is formedwith an inwardly projectformed yin the detent shoulder 31, whereby thedisc 24 i '1 will be held against counter-clockwise rotation when lug 34engages the shoulder 35, as viewed in FIGURE 4. By manually rotating thelever 29 in a counter-clockwise direction, as viewed in FIGURE 4, fromthe full line position thereof tothe dotted view position thereof, thetrailing end 47 of shoulder 35 may be moved inwardly'sufficiently toallow the lug 34 to clear same.

{'Ihe locking lever 29, in its full line position, shown in FIGURE 4,establishes the starting position of the ratchet disc 24. v

Designated at 36V is an opaque cover member rwhichis secured on the base12 in overlying relationship to the disc member 24, said cover member 36being formed with a central aperture through which the stud member 25freely extends, as is clearly shown in FIGURE 2. The

` cover member 36 is of identical shape tol-the base 12, as

shown lin FIGURES 1 and 2.

The ratchet disc 24 is inscribed with a ,plurality of concentric rows ofalphabetical letter grade ,marks, said rows being shown at 37. Theangular spacing between adjacent grade letters of said rows is exactlythe same as Patented Oct. 19,61`

the angular spacing between adjacent ratchet teeth 28 of the disc.

The cover member 36 is formed with the radially extending window oraperture 38 which transversely overlies vthe vrows of grade marks 37,the side margin of window 38 being provided ,with a scale 39 identifyingthe respectiverows, in terms of numerals representing the number ofgrades whose average is to be taken.

The cover member 36 is further inscribed adjacent the handle 20 o=f theoperating arm 16 with a grade scale 40, comprising the series of gradeswhose average may be computed, the grades being arranged in descendingorder, as shown in FIGURE l, and being spaced along the periphery of thecover 36 by the same angular spacings as the ratchet `teeth 28, the rstgrade calibration 41 being spaced from the index line 21 of the handleZtl, with the handle in its zero position in recess 15, by a spacingequivalent to the angular spacing between two successive ratchet teeth28. The rows of grade marks 37 comprise grade marks calibratedin'accordance with the sum of the number of ratchet teeth moved by thearm 16 during a series of rotations of the disc member 24 and inaccordance with the number of such rotations. Speciiically, each grademark value in the rows 37 is determined by dividing the sum of thenumber of ratchet teeth moved by the arm 16 during a series of rotationsof the disc rnember24 by the arm 16 by the number of such rotations, thenumerical value thus obtained being correlated with an alphabeticalgrade value in a manner readily understood. Thus, in computing anaverage grade, the user successively rotates the disc member 24 throughangles corresponding to the various grades to be averaged, each gradebeing included in the total to be averaged by moving knob 21 in acounterclockwise direction, as viewed in FIGURE l, from the startingposition to a calibration 41 corresponding to said grade, and thenreturning the knob 20 -to its starting position. As will be readilyapparent, such a movement of -the operating element 20 rotates the discmember 24 through a number of ratchet teeth angles, corresponding to theparticular grade included in the total to be averaged. Since eachparticular grade represents a specific number of ratchet teeth, thetotal of all the grades will be represented by a total number of ratchetteeth which in turn corresponds to a specic amount of angular rotationof the disc member 24 in a counterclockwise direction from its startingposition. The average number of ratchet teeth is determined by dividingthe total by the number of actual rotations required to produce thetotal. The grade values 37 represent, in terms of alphabetical symbolsthe quotient of the .total number of ratchet teeth divided by the numberof rotations involved in the computation. Thus, the scale numerals 39represent various numbers of rotations, namely, various numbers ofgrades to be averaged, and in the specific example illustrated representfrom two to eight grades -to be averaged, the respective rows ofconcentric scales on the disc member 24 being calibrated to provide thequotient of the total numerical value (number of ratchet teeth) dividedby number of rotations (number of grades to be averaged), translatedinto alphabetical symbols. Thus, to obtain a grade average, it is merelynecessary to rotate the operating arm 20, as above described, throughthe successive angles, corresponding to the various grades, and then todetermine theaverage by observing the value appearing next to the scalenumeral 39 adjacent window Si; corresponding to the number of gradesincluded in the computation. The average grade will be given adjacentthe scale numeral 39 adjacent window 38.

After an average has been obtained, as above described, the disc member24 may be returned to its starting position by rotating the enlarged topend of the stud 25, shown at 40', in a counter-clockwise direction,until the lug element 34 engages the detent shoulder 35 on the lockinglever 29. IThis quickly establishes the starting position of disc member24. The disc member may be released for use in a computation by rotatingthe locking lever 29 in a counter-clockwise direction suiciently toallow lug 34 to clear end portion 47, namely, from the full line viewposition thereof shown in FIGURE 4 to the dotted View position thereof,by means of the upstanding stud element 32 which projects through a slot42 provided in the cover 36. After a compu-tation, the disc member maybe rotated suiiiciently to cause the lug 34 to engage the leading edgeportion 45 of the shoulder 31, thereby causing the locking lever toreturn to its normal locking position wherein the lug 34 is received inthe notch 35, thus reestablishing the starting position of the discmember after the averaging computation.

VAs 4will be readily understood, the locking lever 29 engages betweenthe bottom surface of the recess 43 and the top cover 36 with suiiicientfriction so that it must be manually rotated from its locking positionto its release position.

The average grade marks 37 on the respective concentric rows of grademarks on disc member 24 represent transfer values corresponding to thegrades being averaged, wherein the ratchet teeth are employed as thetransfer means. Thus, in the calibration of the numerical value 37, theoriginal grades may be assigned tooth values corresponding to theirparticular significance. For example, the alphabetical grade Arepresents one tooth, the alphabetical grade A- represents two ratchetteeth, the alphabetical grade B+ represents three teeth, thealphabetical grade B represents four teeth, etc. A series of additionsof alphabetical grades, causes the disc member 24 to be rotated througha number of ratchet teeth angles, corresponding to the sum of theassigned values of the respective grades included in the computation.The sum of the ratchet teeth, divided by the number of rotationsinvolved, would provide a numerical value, which is expressed as analphabetical grade value, in accordance with the original assignment ofnumerical values for the respective grades.- Where the quotient of thetotal number of teeth divided by the number of computations isintermediate between one numerical value and another, the correspondingalphabetical grade may be expressed by two alternative grade values, asshown in certain of the spaces in the concentric rows illustrated inFIGURE 3, whereby the teacher is given the discretion of assigning oneor the other alphabetical grade value to the pupil in question.

The disc member 24 is suitably shaded, as shown at 44, to notify theuser when the starting position is being approached, as the knob 40 isrotated toward said starting position, the shaded area 44 appearingthrough the Window 38 as the disc 24 approaches its starting position.

While a specic embodiment of an improved device for obtaining theaverage of a number of alphabetical grades has been disclosed in theforegoing description, it will be understood that various modificationswithin the spirit of the invention may occur to those skilled in theart. Therefore, it is intended that no limitations be placed on theinvention except as defined by the scope of the appended claim.

Whatis claimed is:

A device for obtaining the average of a number of grades comprising abase, a disc member pivoted centrally on said base andv being inscribedwith a plurality of concentric rows of grade marks, evenly spacedratchet teeth on the periphery of said disc member, said base beingformed with a generally V-shaped recess which includes the center of thebase adjacent the vertex of the recess, a substantially flat armdisposed horizontally in said recess beneath the disc member and pivotedto the center ofthe base in said recess on the same axis as said discmember and projecting radially beyond an edge of saidV base, pawl meanson the arm adjacent the periphery of the base. engageable with saidratchet teeth to rotate the discV member in one direction responsive torotation of said arm in said one direction, second pawl means beingcalibrated in accordance with a value determined by dividing the sum ofthe number of ratchet teeth moved by the arm during a series ofrotations of the disc member by the number of such rotations, said covermember being provided adjacent said arm with a scale of radial ymarkings corresponding to the different grades and angularly separatedby the same angular spacing as the successive ratchet teeth, a resetknob centrally secured to said disc member and extending through saidcover member, and manually releasable cooperating detent means on thebase and on the disc member formed and arranged'k to at times preventrotation of` said disc member beyond member, a detent arm pivoted tosaid base and having a detent notch lockingly engageable with said lug,and means to manually rotate said detent arm` suiciently to disengagesaid detent notch from said detent lug. y

` References Cited in the file of this patent UNITED STATES PATENTS640,850 work Jan. 9, i900 748,924 Buresh l.'an. 5, 1904 1,729,714Ellison Oct. 1, 1929 1,765,697 Palmer et al June 24, 1930 FOREIGNPATENTS 819,737 Germany Nov. 5, 1951 286,168 Switzerland Feb. 2,

